1. Field of the Invention
The present device relates to a chain guide structure to be incorporated into a motorcycle.
2. Description of Background Art
When mounting a chain guide to extend along a chain wound round a driving sprocket supported on the sidewall of a crankcase on the engine together with a cover to be attached to the sidewall of the crankcase so as to cover the driving sprocket, the chain guide is placed temporarily on the inner surface of the cover. The cover temporarily holding the chain guide is positioned on the sidewall of the crankcase so as to cover the sprocket, and then the chain guide and the cover are fastened together to the sidewall of the crankcase with screws.
A first conventional chain guide structure, as disclosed in Japanese Utility Model Publication No. 1-27512, includes a chain guide provided with projections on its outer surface and a chain cover provided with recesses in its inner surface. The chain guide and the chain cover are assembled temporarily by .inserting the projections of the chain guide into the recesses of the cover. The first conventional chain guide structure has a complicated construction because the chain guide must be provided with projections and the chain cover must be provided with recesses.
A second conventional chain guide structure includes a chain guide provided with holes and a chain cover provided with projections in its mating surface. The chain guide and the chain cover are assembled temporarily by placing the chain guide on the chain cover so as to receive the projections of the chain cover in the holes of the chain guide, respectively.
A third conventional chain guide structure is formed by welding a chain guide to a chain cover. The third conventional chain guide structure requires a welding process. Once welded together the chain guide and the chain cover cannot individually be replaced with a new one because the chain guide is welded to the chain cover.